* {
  margin: 0;
  padding: 0;
  list-style: none;
}

.box {
  margin: 0 auto;
  width: 500px;
  height: 200px;
}

.box>.img_box {
  position: relative;
  overflow: hidden;
}

.box>.img_box>ul {
  white-space: nowrap;
  font-size: 0;
  /* transition: 0.2s ease-in-out; */
}

.box>.img_box>ul>li {
  display: inline-block;
  width: 500px;
}

.box>.img_box>ul>li>a>img {
  width: 100%;
}

.box>.img_box>.arrow_left,
.box>.img_box>.arrow_right {
  width: 30px;
  height: 50px;
  text-align: center;
  line-height: 50px;
  font-size: 20px;
  background-color: rgba(0, 0, 0, 0.2);
  transition: 0.3s linear;
  cursor: pointer;
  color: aliceblue;
}

.box>.img_box>.arrow_left:hover,
.box>.img_box>.arrow_right:hover {
  background-color: rgba(0, 0, 0, 0.8);
  width: 35px;
}

.box>.img_box>.arrow_left {
  position: absolute;
  top: 30%;
  left: 0;
}

.box>.img_box>.arrow_right {
  position: absolute;
  top: 30%;
  right: 0;
}

.box>.dot_box {
  text-align: center;
}

.box>.dot_box>span {
  display: inline-block;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background-color: gray;
  margin: 0 3px;
  cursor: pointer;
}

.box>.dot_box>span:hover {
  background-color: #f00;
}